British intelligence ran a campaign designed to exaggerate Iraq's weapons of mass destruction, a former US intelligence officer has claimed.

Former UN chief weapons inspector Scott Ritter said the disinformation drive in the late 1990s was designed to shift public opinion.

Mr Ritter has been a vocal critic of military action against Iraq since leaving the inspections team in 1998.

A spokesman for MI6 said the allegations were "unfounded".

He told reporters in the House of Commons that he was
involved personally with Operation Mass Appeal between the summer of
1997 until August 1998 when he resigned from the UN.

Mr Ritter said the MI6 operation was designed to "shake up public
opinion" by passing dubious intelligence on Iraq to the media.

The so-called "non-actionable intelligence" dealt with Saddam Hussein's
alleged campaign to possess and conceal weapons of mass destruction.
He said the intelligence was "single source data of dubious quality".

Mr Ritter claimed this was the first time the existence of Operation
Mass Appeal had been revealed.

He urged MPs to hold a fresh inquiry in the use of intelligence in the run up to the war against Iraq.

He declined to give specific examples of disinformation but said he was
prepared to reveal details before a public inquiry.

Dubious data

Mr Ritter said: "I was brought into the operation in 1997 because at the UN... I sat on a body of data which was not actionable, but was sufficiently sexy that if it could appear in the press could make Iraq look like in a bad way.

"I was approached by MI6 to provide that data, I met with the Mass
Appeal operatives both in New York and London on several occasions.
This data was provided and this data did find its way into the
international media.

"It was intelligence data that dealt with Iraq's efforts to procure
WMDs, with Iraq's efforts to conceal WMDs. It was all single source
data of dubious quality, which lacked veracity.

"They took this information and peddled it off to the media,
internationally and domestically, allowing inaccurate intelligence
data, to appear on the front pages.

"The government, both here in the UK and the US, would feed off these media reports, continuing the perception that Iraq was a nation ruled by a leader with an addiction
to WMDs."

A spokesman speaking on behalf of MI6 told BBC News Online: "The allegation that Ritter was using MI6 material is unfounded."